Hacker News new | ask | show | jobs
by blueflow 737 days ago
Why twice? You can keep the fake laptop.

The OS does not matter? Grab the video output via HDMI/DisplayPort and insert the keypresses via USB. Thats likely gonna work. Basically what modern KVM switches do. And setup the fake laptop as VNC client. Same tech that companies can use to remotely manage servers.
1 comments
Foxboron 737 days ago
> The OS does not matter?

Of course it does. You are replaying the logos and screens.

> Grab the video output via HDMI/DisplayPort and insert the keypresses via USB. Thats likely gonna work. Basically what modern KVM switches do. And setup the fake laptop as VNC client. Same tech that companies can use to remotely manage servers.

You believe you can boot up an entire VNC client to display something that would take most machines under a second to display?

link
blueflow 737 days ago
> You are replaying the logos and screens

Which the real machine happily gives me via HDMI/DisplayPort.

> You believe you can boot up an entire VNC client to display something that would take most machines under a second to display?

Do i need to? That the user presses the power button does not mean the machine will freshly boot. It could also be an unsuspend/wakeup or some regular ACPI event if the machine is only appearing to be off.

link
Foxboron 737 days ago
> Do i need to? That the user presses the power button does not mean the machine will freshly boot. It could also be an unsuspend/wakeup or some regular ACPI event if the machine is only appearing to be off.

This is a completely imaginary scenario. I'd be amazed to see it pulled off.

EDIT: I hear Amazon is still getting pitches for Hacker 2. You might have a shot.

link
orf 736 days ago
OP is trying to say that this TPM TOTP approach doesn’t help verify a machine is legitimate if there is a possibility that the machine you’re using has been swapped with a malicious one.

This doesn't really mesh well with what the TPM-TOTP idea is trying to solve: trust in the machine you’re using.

Hyperbolic or fairly extreme-sounding scenarios are common when discussing this kind of thing, partly because it makes discussion about a fairly boring topic a little bit more interesting. Don’t get distracted by that.

That being said, using a TPM-based TOTP is pretty extreme sounding in and of itself.

link
Foxboron 736 days ago
> Hyperbolic or fairly extreme-sounding scenarios are common when discussing this kind of thing, partly because it makes discussion about a fairly boring topic a little bit more interesting. Don’t get distracted by that.

It's not. They are very much intended to derail serious discussions around threat models.

> That being said, using a TPM-based TOTP is pretty extreme sounding in and of itself.

It's not. It's trivial to implement.

link
blueflow 737 days ago
Windows Fastboot (active per default) is suspend disguised as shutdown:

https://www.windowscentral.com/how-disable-windows-10-fast-s...

link
hedora 736 days ago
I'd like to add that the VNC relay machine only has to fool the end user once. So, the attacker wins as long as they think "the bios is a bit janky this morning, and this is more kernel panicky than usual", and type their pin/password anyway.

Of course, it's much easier to just pop the original laptop open and interpose on the keyboard. Even easier: use acoustics to snoop the keystrokes. The snooper could even be 5g/wifi/gps, assuming it's easy to steal some power from the mainboard. I guess fingerprint + camera ID make that attack harder. Still, the hypothetical device could stream HDMI at a few FPS if it was easy to splice into the display panel cable. (I haven't cracked a laptop recently, but those used to be socketed + unencrypted.)

Miniaturization is weird. The latter attack is probably easier to pull off these days than the former. If you wanted to swap my laptop, you'd need to replicate the dents and stickers. Good luck doing that!

link